//==========================================================================
// Copyright (c) 2000-2008,  Elastos, Inc.  All Rights Reserved.
//==========================================================================
/*
;***
;llshr.asm - long shift right
;
;       Copyright (c) 1985-1997, Microsoft Corporation. All rights reserved.
;
;Purpose:
;   define signed long shift right routine
;       __allshr
;******************************************************************************

;***
;llshr - long shift right
;
;Purpose:
;   Does a signed Long Shift Right
;   Shifts a long right any number of bits.
;
;Entry:
;   EDX:EAX - long value to be shifted
;   CL    - number of bits to shift by
;
;Exit:
;   EDX:EAX - shifted value
;
;Uses:
;   CL is destroyed.
;
;Exceptions:
;
;*****************************************************************************/

//==========================================================================
// Copyright (c) 2000-2004,  Elastos, Inc.  All Rights Reserved.
//==========================================================================
//
// The original program was copied from Microsoft Visual Studio 6.0
// Enterprise Edition.  This file is adapted for Zee operating system.
//==========================================================================

#include <elatypes.h>

__declspec(naked) void __cdecl _allshr(void)
{
    __asm {
;
; Handle shifts of 64 bits or more (if shifting 64 bits or more, the result
; depends only on the high order bit of edx).
;
    cmp cl,64
    jae short RETSIGN

;
; Handle shifts of between 0 and 31 bits
;
    cmp cl, 32
    jae short MORE32
    shrd    eax,edx,cl
    sar edx,cl
    ret

;
; Handle shifts of between 32 and 63 bits
;
MORE32:
    mov eax,edx
    sar edx,31
    and cl,31
    sar eax,cl
    ret

;
; Return double precision 0 or -1, depending on the sign of edx
;
RETSIGN:
    sar edx,31
    mov eax,edx
    ret
    }
}
